Duplex method of and apparatus for sending telegraphic messages



Dec. 15, 1925. 1.565.508

, E. s. SANDYBERG DUPLEX METHOD OFAND APPARATUS FOR SENDING TELEGRAPHIQ MESSAGES Original Filed Sept. 4, 1930 2 Sheets-Sheet 1 Dee. 15

' 1,565,508 E. s. SANDBERG DUPLEX METHOD OF AND APPARATUS FOR SENDING TELEGRAPHIC-MESSAGES Original Filed Sept. 4, 1920 2 Sheets-Sheet 2 z'g'. g7,

INVENTOR:

Patented Dec. 15, 1925.

UNITED STATES 1,565,508 PATENT OFFICE.

EUGENE SIXTEN SANDBERG, OF HARRISBURG, PENNSYLVANIA, ASSIGNOR OF FIF- TEEN FER, CENT T H. O. S. SL'ANDBEBG, OF HARRISBURG, PENNSYLVANIA, AND

TEN PER CENT TO LELAND B. NENELL,

DUPLEX METHOD or AND APPARATUS Application filed September 4, 1920, Serial To all whom it may concern.

Be it known that I, EUGENE S. SANnnn-Re, a citizen of the United State, and resident of the city of Harrisburg, in the county of Dauphin and State of Pennsylvania, have invented certain .new and useful Improvements in Duplex Methods of and Apparatus for Sending Telegraphic Messages, of which the following is a specification.

This invention relates generally to an improvement in telegraph systems, and particularly to the provision of means whereby in the use oi an alternating current on the main line, such current may at the several stations be divided into two phases of positive and negative pulsations, with such pulsations controlled so as to operate two separate and distinct sets of telegraph instruments, thereby to provide two separate and distinct channels for the transmission and receipt of telegraphic signals.

The invention in its concrete form is embodied in what may be termed a dividing relay having spaced contacts in circuit with r the respective sets of telegraph instruments,

combined with an element controlled by the alternating current and tuned to vibrate at exactly the same number of vibrations per second as does the alternating current used, so that thereby all pulsations of one charac ter may be led through one contact, and the pulsations of the opposite character led through the other contact. I

The alternating current is thus mechanically divided, the pulsations of any one character being provided with a metallic conductor to the particular telegraph instruments, while the other instruments are cut out through an intervening air gap, Only one current path is possible at a time, and if the respective" paths are alternately provided in exact synchronism with the alternating current pulsations, such alternating current is actually divided to provide two distinct and. separate forces over the wire, which may obviously be used for the sending and receiving of two distinct and separate sets of signals at practically the same time. I

The instrument here shown as the 'concrete embodiment of this invention includes a resistance of a character materially exceeding the total resistance of the whole circuit, which resistance serves to provide a OF SPRINGFIELD, ILLINOIS.

FOR SENDING TELEGBAPHIG MESSAGES.

No. 408,147. Renewed. September 19, 1925.

path for the alternating current passing through the instrument, in the event both keys connected with the particular instrument are opened when a signal is made from another station on the line, thereby to maintain the continuity of the alternating current path through the instrument and thus insure the continuous operation of the vibrating element.

The invention is illustrated in the accompanying drawings, in which Fig. 1 is a perspective view of the instrument.-

Fig. 2 is a bottom plan view of the same.

Fig. 3 is a diagrammatic view illustrat ing more particularly the wiring of the instrument, and showing the telegraph instruments connected therewith.

Fig. 4 is a diagrammatic view showing a series of stations on the main line.

The improved. instrument, in the preferred, but not necessarily the only, form of details, comprises an insulating base 1, on which is mounted in spaced relation contact posts 2 and 3. Rods 4; and 5 are adjustably mounted in the upper ends of the posts 2 'and 3, respectively, the rods having contact tips of appropriate material to insure the most efiiective current path in the action of the vibrating member to be later referred to.

A polarized wound magnet 6 is supported upon the base including spaced cores 7 and 8 so wound that both cores are alternately North and, South poles when the current is passing through the coils. A permanent magnet strip 9 is secured to both cores, so that the cores form a continuation of the permanent magnet, the oppositeend 10 of this permanent magnet underlying the pole I pieces 11 and 12 of the cores. If both cores are, for example, North poles, the lower end 10 of the permanent magnet becomes a South pole. hen a current is passed through the coils, say, a positive current, one of the cores changes polarity, becoming a South pole, while the other core remains a North pole with greatly increased intensity. When a negative current passes through the coils, the pole which was made a South pole by the positive pulsation changes to a North pole, and the pole which remains North under the influence of the positive pulsation changes to a South pole.

A post 13 is secured upon the base, which may be divided to receive and. rigidly secure one end of a vibrating member 14, the opposite end of which extends equal distances from and between the polepieces 11 and 12 ot the respective cores. Secured upon the vibratingmember, which is preferably a metallic spring strip, are contact strips 15 and, 1G res tiectively. These strips are arranged on opposite sides of the vibrating member and have their free ends spaced an appropriate distance from said vibrating member, in order that such contact strips may have more or less resiliency to insure a good contact. A contact point is carried by each contact strip, as at 17 and 18, and these points are adapted, when the vibrating member is in appropriate position, to engage the contact terminals of the rods 4 and respectively.

The base 1 is preferably supported upon a metallic rim 1!), and within the space atforded by the rim, there is secured to the under side of the base 1 a resistance element 20, which may be of any appropriate character so long as it exceeds, say, live or six times the total resistance of the telegraphic line from end to end. The base 1 is also provided with main wire binding-posts 21, 22, adjacent the magnet, and three additional binding-posts 23, Q-t, and 25, to provide for the connections of the respective sets of telegraph instruments.

The wiring diagram for the dividing re lay constructed in the preferred form described is illustrated more particularly in Fig. The main line 26 is adapted to be connected to one of the binding-posts, as 21, from which a conductor extends to the coil about one of the cores, as T of the magnet 6, and thence through conductor 27 to the otherv coil. From such lastna1ned coil, a conductor 28 leads to the post 13. The post 2 of the vibrating contact circuit is in connection with one of the telegraph instrument binding posts as 2-1- t'hrough a conductor 29, the other post 3 being in circuit to a conductor 30 with the other telegraph instrument bindiugpost as 23. The bindingpost 25 constitutes the instrument connection for the conductor common to both sets of telegraph instruments, and 'a conductor 8-1 extends therefrom to the remaining main wire binding-post 22, to which the main wire 26 is connected. The resistance 20 is in circuit through conductors 32 and 33 with the post 18 and conductor 31, the resistance thus serving to maintain a permanent circuit path for the main line current through the instrument independently of the telegraph instrument circuits. Main line current can. therefore continue to flow through the relay by way of the magnet winding, the resistance 20 and conductor wires 28, E32 and 33, when the instruments 33-1 and 353 are inoperative. These instruments indicated respectively at and 35 are in circuit through conductors 36 and 37 with the respective binding-posts 24 and 23, a common conductor 38 leading to the binding post The circuits of the instrument proper as de scribed are permanent, and the arious conductors referred to are preferably secured on the under side of the base, in the usual manner.

Assuming analternating current passing over the main line, the spring steel vibrating member, which when in position described has its free end between the bow pieces 01 the cores when considered horizontally, and above the permanent South pole of the permanent magnet 9 considered vertically, becomes magnetized by the South pole and is compelled to seek the opposite pole, which said opposite pole is alternately provided by the pole pieces of the cores in accordance with the particular current pulsations, as has been previously described. \Vhen the vibrating member has been moved to one side by the current, the inherent tension thus brought into action is sufficient to carry the vibrating member to the other pole piece in time to make contact for the next current pulsation in the opposite direction. This pulsation magnetizes the cores so as to give the vibrating member a slight pull, acting to tension the particular contact strip 15 or 16 being brought into action. This additional magnetic pull on the vibrating member also gives it that tension as will cause it to move to the opposite pole piece when released, in time for the next pulsation. The member let is thus tuned to vibrate at exactly the same number of vibrations as there are complete cycles of alternating current.

Under this action of the vibrating memher the respective posts 4i. and 5 receive the current, one receiving all positive pulsations, and the other all negative pulsations. These respective pulsations, which may now be treated as independent current in effect, are led through the respective conductors as 29 and 30, to the respective sets of telegraph instruments 3% and The circuit is complete through the common return 38, post 25, conductor 31, post 22, to the main line.

The resistance 20 is designed and effective for maintaining the current divisions described by the instrument, notwithstanding the fact that either or both of the keys of the telegraph sets may be opened. This resistance unit bridges the circuit of the instrument beyond the final magnet coil and the return, and obviously maintains the current flowing through the magnet coils, if either or both of the telegraph sets, circuit or circuits, are ope ed. This resistance is not in eflect a short on the instrument, as, owing to the high resistance of the unit, the telegraph instruments and lines beyond the vibrating member constitute the real duced materially in amperage throughout the full circuit of similar pulsations, and the sounders in this circuit will not work, as they are not sufiiciently sensitive to respond to the low amperage. The polarized magnet, however, is designed to be so sensitive, that said low amperage is sufficient to maintain action of the vibrating member.

In Fig. a there is shown a telegraph circuit with three stations cut in. In this figure A represents the polarized magnet of the respective instruments, B the main line, C the vibrating member of the instrument, D the resistance unit for each instrument, E the keys of the respective telegraph sets, and F the sounders. The operation here is, of course, that previously described, and no further explanation of this particular arrangement is believed necessary herein.

The present system based upon the improved instrument herein described differs from the ordinary duplex system in that such systems are limited to two stations and constitute two one-way channels; while the present system is not restricted as to the number of stations that may be cut in, and constitutes two two-way channels. The present system is not designed to be used extensively in combination with the Morse relay, but can be so used where it is necessary.

Having thus described this invention, it is evident that many minor changes may be made therein without departing from the spirit of this invention or the scope of the following claims:

1. A ciu'rent-dividing relay for telegraph lines using alternating current, comprising a polarized magnet influenced by the alternating current, a vibrator in the alternating current circuit and operated by said magnet to vibrate in synchronism with the alternating current, contact posts forming terminals of independent line circuits including telegraph instrument sets, said posts being alternately engaged by the vibrator on each complete cycle of movement, and a high resistance unit in series with the polarized magnet having one end operatively connected with the magnet and its other end to a contact post to be engaged by a main line wire.

2. An alternating current-dividing relay for telegraph systems, including a magnet having a permanent pole, the other pole being formed of spaced cores, coils about the respective cores for the passage of the alternating current to change the polarity of the cores in accordance with the direction of current, a vibrator within the influence of the permanent pole and movable between and under the influence of the core poles as determined by the pulsation of alternating current, said vibrator being in the alternating current circuit, independent telegraph instrument lines, and means operative by the vibrator in a complete cycle of movement to successively energize said lines with a particular. and distinctive alternating current pulsation.

3. An alternating current-dividing relay for telegraph systems, including a magnet having a permanent pole, the other pole being formed of spaced cores, coils about the respective cores for the passage of the alternating current to change the polarity of the cores in accordance with the direction of current, a vibrator within the influence of the permanent pole and movable between and under the influence of the core poles as determined by the pulsation of alternating current, said vibrator being in the alternatingvcurrent circuit, independent telegraph instrument lines, and means operative by the vibrator in a complete cycle of movement to successively energize said lines with a particular and distinctive alternating current pulsation, and a high resistance unit bridging the alternating current path beyond the polarized magnet to avoid current interruption, when either telegraph instrument line is opened.

4-. A relay for telegraph systems, said relay utilizing a vibrating reed and magnet for the same as a current-carrier, an autosynchronizing means, and a high resistance bridge in circuit with a main line wire and the winding of said magnet to maintain the continuity of the line when the vibrating lUU reed ceases to function as a current-carrier.

, ments are operative and permitting the passage of current along the main line and through the same when the instruments are inoperative.

6. A relay for telegraph systems employing alternating current comprising a base, a polarized magnet on said base, means operable by said magnet for directing corresponding alternations of the current of the system to station receiving instruments connected to said relay, and bridging means for directing current past the relay along a main line and including an element rendering said means operative only when the relay is inoperative.

7. In a telegraph system utilizing alternating current, two or more sets of receiving instruments for each station of the system, a control relay for each station of the system and operable for directing the positive alternations of the current of the system to one or more of the said sets of receiving instruments and directing the negative a1- ternations of the current of the system to the remaining sets of instruments, and bridging means "for diverting the main line current past the station when the said station is inope "ative.

8. A relay for telegraph systems employing alternating current comprising a base, polarized magnets mounted on one end of said base, a post mounted near the opposite end of said base, a vibrating member carried by said post and extending between the poles or said magnets, a plurality of sets of receiving instruments in circuit with said polarized magnets and said vibrating member, means for directing the positive alternations of the current of the system from said vibrating member to certain of said sets of receiving instruments and the negative alternations of the said current to the remaining sets of receiving instruments, and a resistance element carried by said base exceeding the resistance of the total resistance of the telegraph line from end to end, said resistance element being in circuit with said post and the main line and thus servin g to maintain a permanent circuit path for the main line current through the relay independent of 'the telegraph receiving instrument circuits.

In testimony whereof I hereunto aflix my signature.

EUGENE SIXTEN SANDBERG. 

